Recent studies have implicated the importance of high density lipoprotein cholesterol as being an independent risk factor in the genesis of atherosclerosis. Studies have shown that individuals with a low amount of high density lipoprotein cholesterol tend to be at more risk for the development of ischemic heart disease and myocardial infarction. We are studying lipoprotein composition in Indians and Caucasians. Cholesterol and triglycerides are being measured in high density lipoproteins as well as other lipoprotein subclasses isolated by ultracentrifugation. These parameters are being compared in groups of normal and diabetic Indians with and without coronary artery disease, and the influence of therapy is being assessed. In addition, free fatty acid levels are being studied because of their precursor relationship to lipoproteins and their reflection of insulin action. From this study we will attempt to determine if diabetes is associated with changes in serum lipoproteins, and to delineate the importance of high density lipoprotein cholesterol values in the pathogenesis of ischemic heart disease.